ACHIEVING ACTION LEVELS: 4.0, 2.7, 2.0
4.0 pCi/L
Achieving below the USEPA action level of 4.0 pCi/L can be accomplished for virtually any home. Older homes can present challenges due to construction practices when they were built and in special cases it can become a question of expense versus benefit.
2.7 pCi/L
The World Health Organization (WHO) has recently modified their recommended action level from about 5.3 pCi/L to about 2.7 pCi/L. This reflects recommendations regarding life-long, direct exposure. The change reflects recent population studies for statistical evidence of radon induced lung cancer.
2.0 pCi/L
The USEPA recommends to consider action between 2 and 4 pCi/L since no exposure is safe. However, around about 2.0 pCi/L and lower, the lower limits of sensitivity for test devices has been reached and errors up to 300% have been seen to occur. Hence, verifying less than 2.0 pCi/L is not truly feasible (though some contractors knowingly or unknowingly make such claims or warranties).
0.7 pCi/L
Outside air anywhere on earth. This is so low that even the best equipment scientists use can only estimate between 0.4 to 0.8 pCi/L.
EXPECTATIONS AFTER RADON SYSTEM INSTALLATION:
One can expect reductions to below 4 pCi/L. More often retests show close to outside air (or below 2.0 pCi/L) in the worst case basement areas. (Note however that readings around 2.0 or lower are below the range most devices are capable of for accurate measurement.) Radon Concentrations in areas above a basement where people may spend more time are often 1/3rd to 1/2 the basement concentrations.
Note, about one in ten systems need adjustment. Retest quickly after installation with a continuous monitor where hourly readings can help identify problems and verify success. Thereafter, home test kits may be recommended as an independent, inexpensive and effective method for continued verification. |
